receive-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "run-command.h"
   5 #include <sys/wait.h>
   6
   7 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
   8
   9 static const char unpacker[] = "git-unpack-objects";
  10
  11 static int show_ref(const char *path, const unsigned char *sha1)
  12 {
  13         packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
  14         return 0;
  15 }
  16
  17 static void write_head_info(void)
  18 {
  19         for_each_ref(show_ref);
  20 }
  21
  22 struct command {
  23         struct command *next;
  24         unsigned char updated;
  25         unsigned char old_sha1[20];
  26         unsigned char new_sha1[20];
  27         char ref_name[0];
  28 };
  29
  30 static struct command *commands = NULL;
  31
  32 static int is_all_zeroes(const char *hex)
  33 {
  34         int i;
  35         for (i = 0; i < 40; i++)
  36                 if (*hex++ != '0')
  37                         return 0;
  38         return 1;
  39 }
  40
  41 static int verify_old_ref(const char *name, char *hex_contents)
  42 {
  43         int fd, ret;
  44         char buffer[60];
  45
  46         if (is_all_zeroes(hex_contents))
  47                 return 0;
  48         fd = open(name, O_RDONLY);
  49         if (fd < 0)
  50                 return -1;
  51         ret = read(fd, buffer, 40);
  52         close(fd);
  53         if (ret != 40)
  54                 return -1;
  55         if (memcmp(buffer, hex_contents, 40))
  56                 return -1;
  57         return 0;
  58 }
  59
  60 static char update_hook[] = "hooks/update";
  61
  62 static int run_update_hook(const char *refname,
  63                            char *old_hex, char *new_hex)
  64 {
  65         int code;
  66
  67         if (access(update_hook, X_OK) < 0)
  68                 return 0;
  69         code = run_command(update_hook, refname, old_hex, new_hex, NULL);
  70         switch (code) {
  71         case 0:
  72                 return 0;
  73         case -ERR_RUN_COMMAND_FORK:
  74                 die("hook fork failed");
  75         case -ERR_RUN_COMMAND_EXEC:
  76                 die("hook execute failed");
  77         case -ERR_RUN_COMMAND_WAITPID:
  78                 die("waitpid failed");
  79         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
  80                 die("waitpid is confused");
  81         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
  82                 fprintf(stderr, "%s died of signal", update_hook);
  83                 return -1;
  84         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
  85                 die("%s died strangely", update_hook);
  86         default:
  87                 error("%s exited with error code %d", update_hook, -code);
  88                 return -code;
  89         }
  90 }
  91
  92 static int update(const char *name,
  93                   unsigned char *old_sha1, unsigned char *new_sha1)
  94 {
  95         char new_hex[60], *old_hex, *lock_name;
  96         int newfd, namelen, written;
  97
  98         namelen = strlen(name);
  99         lock_name = xmalloc(namelen + 10);
 100         memcpy(lock_name, name, namelen);
 101         memcpy(lock_name + namelen, ".lock", 6);
 102
 103         strcpy(new_hex, sha1_to_hex(new_sha1));
 104         old_hex = sha1_to_hex(old_sha1);
 105         if (!has_sha1_file(new_sha1))
 106                 return error("unpack should have generated %s, "
 107                              "but I can't find it!", new_hex);
 108
 109         safe_create_leading_directories(lock_name);
 110
 111         newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 112         if (newfd < 0)
 113                 return error("unable to create %s (%s)",
 114                              lock_name, strerror(errno));
 115
 116         /* Write the ref with an ending '\n' */
 117         new_hex[40] = '\n';
 118         new_hex[41] = 0;
 119         written = write(newfd, new_hex, 41);
 120         /* Remove the '\n' again */
 121         new_hex[40] = 0;
 122
 123         close(newfd);
 124         if (written != 41) {
 125                 unlink(lock_name);
 126                 return error("unable to write %s", lock_name);
 127         }
 128         if (verify_old_ref(name, old_hex) < 0) {
 129                 unlink(lock_name);
 130                 return error("%s changed during push", name);
 131         }
 132         if (run_update_hook(name, old_hex, new_hex)) {
 133                 unlink(lock_name);
 134                 return error("hook declined to update %s\n", name);
 135         }
 136         else if (rename(lock_name, name) < 0) {
 137                 unlink(lock_name);
 138                 return error("unable to replace %s", name);
 139         }
 140         else {
 141                 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
 142                 return 0;
 143         }
 144 }
 145
 146 static char update_post_hook[] = "hooks/post-update";
 147
 148 static void run_update_post_hook(struct command *cmd)
 149 {
 150         struct command *cmd_p;
 151         int argc;
 152         char **argv;
 153
 154         if (access(update_post_hook, X_OK) < 0)
 155                 return;
 156         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 157                 if (!cmd_p->updated)
 158                         continue;
 159                 argc++;
 160         }
 161         argv = xmalloc(sizeof(*argv) * (1 + argc));
 162         argv[0] = update_post_hook;
 163
 164         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 165                 if (!cmd_p->updated)
 166                         continue;
 167                 argv[argc] = xmalloc(strlen(cmd_p->ref_name) + 1);
 168                 strcpy(argv[argc], cmd_p->ref_name);
 169                 argc++;
 170         }
 171         argv[argc] = NULL;
 172         run_command_v(argc, argv);
 173 }
 174
 175 /*
 176  * This gets called after(if) we've successfully
 177  * unpacked the data payload.
 178  */
 179 static void execute_commands(void)
 180 {
 181         struct command *cmd = commands;
 182
 183         while (cmd) {
 184                 cmd->updated = !update(cmd->ref_name,
 185                                        cmd->old_sha1, cmd->new_sha1);
 186                 cmd = cmd->next;
 187         }
 188         run_update_post_hook(commands);
 189 }
 190
 191 static void read_head_info(void)
 192 {
 193         struct command **p = &commands;
 194         for (;;) {
 195                 static char line[1000];
 196                 unsigned char old_sha1[20], new_sha1[20];
 197                 struct command *cmd;
 198                 int len;
 199
 200                 len = packet_read_line(0, line, sizeof(line));
 201                 if (!len)
 202                         break;
 203                 if (line[len-1] == '\n')
 204                         line[--len] = 0;
 205                 if (len < 83 ||
 206                     line[40] != ' ' ||
 207                     line[81] != ' ' ||
 208                     get_sha1_hex(line, old_sha1) ||
 209                     get_sha1_hex(line + 41, new_sha1))
 210                         die("protocol error: expected old/new/ref, got '%s'", line);
 211                 cmd = xmalloc(sizeof(struct command) + len - 80);
 212                 memcpy(cmd->old_sha1, old_sha1, 20);
 213                 memcpy(cmd->new_sha1, new_sha1, 20);
 214                 memcpy(cmd->ref_name, line + 82, len - 81);
 215                 cmd->next = NULL;
 216                 *p = cmd;
 217                 p = &cmd->next;
 218         }
 219 }
 220
 221 static void unpack(void)
 222 {
 223         int code = run_command(unpacker, NULL);
 224         switch (code) {
 225         case 0:
 226                 return;
 227         case -ERR_RUN_COMMAND_FORK:
 228                 die("unpack fork failed");
 229         case -ERR_RUN_COMMAND_EXEC:
 230                 die("unpack execute failed");
 231         case -ERR_RUN_COMMAND_WAITPID:
 232                 die("waitpid failed");
 233         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
 234                 die("waitpid is confused");
 235         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
 236                 die("%s died of signal", unpacker);
 237         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
 238                 die("%s died strangely", unpacker);
 239         default:
 240                 die("%s exited with error code %d", unpacker, -code);
 241         }
 242 }
 243
 244 int main(int argc, char **argv)
 245 {
 246         int i;
 247         const char *dir = NULL;
 248
 249         argv++;
 250         for (i = 1; i < argc; i++) {
 251                 const char *arg = *argv++;
 252
 253                 if (*arg == '-') {
 254                         /* Do flag handling here */
 255                         usage(receive_pack_usage);
 256                 }
 257                 if (dir)
 258                         usage(receive_pack_usage);
 259                 dir = arg;
 260         }
 261         if (!dir)
 262                 usage(receive_pack_usage);
 263
 264         /* chdir to the directory. If that fails, try appending ".git" */
 265         if (chdir(dir) < 0) {
 266                 if (chdir(mkpath("%s.git", dir)) < 0)
 267                         die("unable to cd to %s", dir);
 268         }
 269
 270         /* If we have a ".git" directory, chdir to it */
 271         chdir(".git");
 272         putenv("GIT_DIR=.");
 273
 274         if (access("objects", X_OK) < 0 || access("refs/heads", X_OK) < 0)
 275                 die("%s doesn't appear to be a git directory", dir);
 276         write_head_info();
 277
 278         /* EOF */
 279         packet_flush(1);
 280
 281         read_head_info();
 282         if (commands) {
 283                 unpack();
 284                 execute_commands();
 285         }
 286         return 0;
 287 }